Spring means for electric switches



' 1 1,629,911 y 1927' B. E. GETCHELL SPRING MEANS FOR ELECTRIC SWITCHES Filed March 10, 1923 'm an IN V EN TOR Patented May 24, 1927.

UNITED STATES PATENT OFFICE.

BENJAMIN GETCI-IELL, OI PLAINVILLE, CONNECTICUT, ASSIGNOR TO THE TRUM- I BULL ELECTRIC MANUFACTURING COMPANY, OF PLAINVILLE, CONNECTICUT, A

CORPORATION OF CONNECTICUT.

SPRING MEANS FOR ELECTRIC SWITCHES.

Application filed-March 10, 1923:. Serial no. 624,141.

My invention relates particularly to-operating springs used in enclosed swltches, and

has for its main object the provision of practical means .for adjusting the tension of the spring. I have'also sought to provide means whichcan be readily installed at a embodying the Improvements of my invention, the switch box being shown open.

Fig. 2 is a longitudinal sectional view with the cover closed and the switch in the closed circuit position.

Fig. 3 is a erspective view of parts of the adjusting evice.

Fig. 4 is a fragmentary side view of the adjustable connection, partly in section.-

The box or receptacle in-the form shown has a .body 5 and a covert; of any suitable construction. The switch proper has one or more blades 7 and an operating crank 8 connected to the switch blade or blades, for instance by means of brackets 9, or in any other'suitable manner. An operating handle 10 is pro- -vided exterior to the box and connected to the operating crank 8.

In the particular form shown theswitch is provided with anelectro-magnet having a coil 11 and an'armature 12 which is hinged at 13. A link 14 is connected at one end to the crank 8 and has a sliding-engagement 15 with the armature 12. One end of the link normally abuts against a roller 16. carried by the armature when. the parts are-in the" closed circuit position with normal cur conform to the coils and .adapted to be.

screwed into the end coils of the spring. The central portion'of the flange 23 is drawn to a diameter approximately equal to that of'the coils of the spring to rovide a retaining shoulder 24 for centermg the mem- Figure 1 is a perspective view'of a switch ber 19 relative to the spring. The end 6r shoulder 24 is further drawn and interiorly threaded as at 20 to receive the end'of' an adjusting screw 18. A check nut 21 is alsof preferably 'provided. The opposite end ot the spring. 17 may be hooked over'a. ring or bushlng 22 on the crank 8.; This construction provides two methods of adjustmentfor the tension onthe spring. For small changes in tension the screwx18 is turned in the threads 20, while for greater.

adjustment the whole member 19 is. screwed into or out of the spring. 7

From this it will be seen that when the Fig. 2 the spring 17 is pullinguponthe crank -8 thus tending to throw the switch switch is in the closed circuit position of into open circuit position. If the current is on and of normal voltage, the ma et coil 11 will hold down the armature 12 in oppo .sitionto the thrust ofthe link or bar- '14 against the roller 16. If the circuit through the c011 11 is opened at some exterior point, or'if the field becomes weakened below a pre-designed value'the armature will be released and the pull of the spring will-be sufiicient to tilt the armature so as'to're-f 7 to be\op'ened. It is important therefore that the tension of the spring be roperly loosen the check nut 21 and turn the screw '18 WlllCh is accessible at the outside of'the box. The member 19 maybe readily screwed -1nto the end coils of the spring 17 and it will be held there securely by the normal tension of the adjacent coils and lateral shifting of the member will be prevented by the shoal gler 24 which fits within the end coils of the spring.

In practice the springs areusually tightwonnd but when in use, the coilsopen up v according to the tension .placed upon the spring.

adjusted tothe conditions under w ich the switch is tov operate. By. my construction 1t Wlll be seen that it is simply necessary to -It is obvious howeverthat all of the coils s the sprin In the manufacture otthe parts at t e factory the member 19 is first screwed into the end of the s ring-17 to a position which is approximate y correct for the particular type of switch in which it is intended to be used. When the parts are assembled in the box the screw 18 is inserted through awall of the box, the nut 21 screwed part way on to the screw and the end of the screw inserted into the member 19. The screw 18 is then adjusted accurately so as to provide exactly the right tension for that particular switch. The check nut 21 is then tightened so as tov hold the screw in fixed .it is obvious that the invention may be applied to any form of switch having a throwing spring of the coiled type or 1n fact to any construction in which it may be desirable to adjust the tension of a coiled spring.

I claim: I

An electric switch construction comprising a box, a switch member within said box, a coiled operating spring connected at one end to said switch member, an anchor member having a flange portion engaged in the coils at the other end of said spring. said anchor member having a threaded neck, an

externally operable adjusting screw passing through one wall of said box and into adjustable engagement in the threaded neck of said anchor member and having a head outside of said box and a lock nut for said ad-.

justing screw inside of said box, the flange of said anchor member being rotatably adjustable in the coils of said spring without rotating said spring.

BENJAMIN E. GETCH'ELL. 

